The present invention generally relates to surgical telescopes, and more particularly embodiments of the present invention relate to a surgical telescope having dual virtual-image screens for comfortable viewing.
Unless otherwise indicated herein, the apparatus and methods described in the background section are not prior art to the claims in this application and are not admitted to be prior art by inclusion in the background section.
Surgical telescopes provide a magnified view of an object that a surgeon is viewing. A magnified view of an object on which a surgeon is operating aids the surgeon in performing a successful surgery. A number of design considerations exist for surgical telescopes, such as relatively high image quality and good ergonomics.
Various known surgical telescopes often trade off high image quality for low comfortable physical use, or trade off high comfortable physical use for low image quality. Known surgical telescopes are typically categorized into three different types of surgical telescopes. A first type, and first generation, of surgical telescopes includes single-lens diopter magnifiers. A second type, and second generation, of surgical telescopes includes surgical telescopes with a preset declination angle. A third type, and third generation, of surgical telescopes includes surgical telescopes having a fully adjustable declination angle. A declination angle is an angle at which a surgeon's eyes must be angled down to look through surgical telescope to see a magnified image of an object.
Surgeons using surgical telescopes often experience strain of the eyes, neck, back, shoulders and arms, and the like. The design aspects of surgical telescopes that effect these strains on the body include declination angle, depth of field and magnification, weight, field of view, frame design, and the like. A surgical telescope with a low declination angle typically provides that a surgeon eyes are similarly positioned at a low declination angle, and to look downward the surgeon must tilt her head downward, tilt her upper body (e.g., shoulders and/or back) downward, or tilt both her head and her upper body downward. A downward tilt of a surgeon's head and/or upper body may cause uncomfortable body strain. A low declination angle, however, does allow a surgeon's eyes to be at substantially the low declination angle providing for reduced strain on the eyes. In contrast a relatively higher declination angle allows for a surgeon's upper body to remain in a relatively more upright and comfortable position if looking down, but requires that a surgeon's eyes be a the higher declination angle (angled downward).
While some surgical telescopes provide for adjustable declination angle, these surgical telescopes often have other design aspects with ergonomics features, which may provide uncomfortable use. For example, various surgical telescopes often have a fixed and relatively shallow depth of field as a result of the magnification provided by the surgical telescopes. A surgeon using a surgical telescope that has a fixed and relatively shallow depth of field generally must move her head and/or body back and forth to keep objects within the depth of field as the surgeon looks at different objects, which are at different distances from the surgeon. Such back and forth movement during a surgical procedure may place physical strains on the surgeon that lead to discomfort. A surgeon might choose a surgical telescope with a wider depth of field to avoid such back and forth movement to improve comfortable use of the surgical telescope, but may have to sacrifice higher magnification for this improved comfortable use.
Thus, there is a need for improved surgical telescopes that provide good ergonomics and a relatively high depth of field with an amount of magnification needed by surgeons.